System for reducing the visibility of objects.



G. BRUSH.

SYSTEM roR REoucmG 1HE vlswlLlrY or oslfcs.

APPLICATION FILED )UNE 2| l9l1. y

Patented Mar. 1l, 1919.

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IIIIYIIiI llllla llnrllrlllllllll ATTORNEY nu man nun rnA man. 'num-vom n t lcumornm snUsH, or DUBLIN, New HAMPSHIRE.

SYSTEM FOB REDUCING THE VISIBILITY F OBJECTS.

Bpeooetion of Letten Patent.

Patented Mar. 11, 1919.

Application mod June 2, 1917. Serial No. 172,558.

T o all whom it may concern.'

Be itknown that I, Genoma BRUSH a citizen of the United States, residing at ublin, in the county of Cheshire and State of New Hampshire, have invented a. new and useful System for Reducing the Visibility of Objects, of which the following is a specilication.

My present invention isin the nature of an improvement u on the process of treating p respective zones, to determine the blending the outsides of o 'ects to make them less visible disclosed 1n Letters Patent No. 715,013, issued on December 2, 1902, to Abbott H. Thayer and myself, jointly.

The illuminating effect of light upon the different surfaces of an object varies substantially as the cosine of the angle of incidence, being maximum when such an le is zero--that 1s to say, when the surface il uminated is perpendicular to the rays of lightand becoming zero when the angle of incidence reaches a right angle; and I have discovered that the most ellective blendings of colors to paint eac of the dillerent surfaces of the object, to secure its invisibility, is obtained by mixin together light an dark colors, white an black for example, in proportions substantially equal, respectively, to the sine and to the complement of the sine-the difference between the sine and the radius-of the angle of incidence of that surface With the shades of color thus obtained for its various surfaces, graduated from dark to light substantially according to the illumi.

nating effect of light thereon, I am able by preventing practically all contrasts of light and shade on an object to secure a nearly perfect monochrome.

I have also discovered that the same monochrome effect can be obtained, without a mixing of the colors, by painting the various surfaces of the object with alternate dark and light stripes or squares, or d ark with regularly disposed light spots or vice versa, proportioning the dark area to the light area on each different surface substantially as the cosine of its angle of incidence.

In the practical ap lication of my invention, I divide all su aces within the qnadrant into a pluralit of divisions or zones representing, accor ing to their angles Aof incidence, substantially equal gradations of illuminations, and determine the proper blendings of colors or shades of palnt to be used, or the proportions of the areas to be reduce the shades with which toof colors for the paint therefor. Thus, the first zone, which is a half zone, extends from the zero angle of incidence to angle cosine ,95, and all surfaces therein are painted black, The second zone, a full zone, extends from angle cosine .95 to angle cosine .85. and all surfaces therein are painted with a blend containing .57 (.57 being approximately the complement of the sine of angle cosine .90)

parts of black to 43 parts of white. Surfaces within the third zone, bounded by angles cosine .85 and cosine .75, are painted with a blend containing:` 40 parts of black to 60 arts of white. For the surfaces within the ourth zone, bounded by the angles cosine .75.and cosine .65, a blend containing 28 arts of black to 72 parts of white is used. he surfaces within the fifth zone, between the an les cosine .65 and cosine .55, are

Beirat with n. blend containin 2O parts of lack to 80 parts of white. I`or surfaces within the sixth zone, between angles cosine .55 and cosine .45, the paint contains 13 parts of black to 87 parts of white. For surfaces within the seventh zone, between angler:` cosine .45 and cosine .35, the paint used contains 5 parts of black to 95 parts of white.

The surfaces within the eighth zone, extending from angle cosine .35 to angle cosine .25,

are ainted with a blend containing 2 parts a of b ack to 98 parts of white. Thc'paint for glo cosine .05 to an angle of 90 degrees, as

colors, ull surfaces within the first zone, 90 per cent. of surfaces within thc second zone 8O per cent. of surfaces within the third zone, etc., are painted black and the remainder of the surfaces within each zone are painted white.

Wi here the object and the source of illumination are both fixed, the angle of incidence of each different surface of the object will, of course, be constant. But where either the source of illumination or thecbJect or both are movable, the angle will be variable. For example, in the case of a ship illuminated by the sun, the an les of incidence upon its surfaces will epend upon the course .and position of the ship andthe timel both of the day and of the year. In the latter cases, it is desirable to determine, somewhat arbitrarily but as definitely as possible, the average zero angle of incidence, which in the case of aiship, varyin with the latitude and time of year, will ap- ,.proximately 80 degrees from perpendicular and from such zero angle as a starting oint to treat the different surfaces of the ollrject so that they will xpresent the color effects .graduated in the manner above described.

The invention will be readily understood by reference to the accompanying drawings, in which Fi re 1 illustrates a scale or instrument which I have devised for the use of painters in practising my new system, and Fig. 2 is an outline view of the outer surfaces of one side of a ship, taken on a transverse section, show' the application to such surfaces of the slilzie of Fig. 1 adjusted for use 1on the assumption that the average zero angle of 4incidence is 30 degrees from perpendicular.

As shown in Fig. 1, a is the scale proper, in the form of a quadrant, and b is a weighted pointer both of which are pivotally mounted at c upon a block (l, also in the form of a quadrant, provided ywith a suitable handle e. The scale is ad'ustably held in. position upon the block A means of a thumbscrew f which passes through an arcu- -ate-slot g in the scale, while the pointer is Vfree to turn by ravit about its pivotal bearing. The ra ial divisions around the periphery of the scale, numbered 1 to 11, are the nine zones and two half zones into which the surfaces to be painted are divided; the cosines and sines of the boundary angles of these zones Vbeing respectively 'indicated by the dotted horizontal and vertical lines merely for the purpose of showing how such 'angles am determlned. The numerals 100, 5 7, 40,'etc., in column near the vertical ed e of the scale, represent ap roximately the complements of the sines shown by light vertlcal lines) of the angles at the centers of illumination of the zones, and -consel qucntly indicate the 1prcentage of the dark color 'to be used in t mixing of the paint with which to paint the surfaces within the respective zones. The numerals 100, 90, 8U, ete., along the horizontal edge of the scale, represent the cosines (shown by light horizontal lines) of the angles at the centers of illumination o f the respective zones, and indicate the percentage of the area of the surfaces therein which are to bepainted dark where such surfaces are painted with alter- 'and then agalnst another of the dilferent surfaces or portions` 'of the surfaces of the ship,.as illustrated in Fig. 2, and the pointer, swinging upon its pivot turns to thevzone within which such sur ace or )ortion of surface is included and so in ioates the proper color effect to be given thereto. Thus, when the scaleis a )lied to a vertical surface :v'the pointer wil indicate that such surface is within the sixth zone and the scale will show that it is to be painted with a blend of colors containing 13 per cent. of black, that is to say, 13 parts of black to 87 parts of white' or, when painted with alternate areas of black and white, that 50 per cent. of the surface is to be painted black and the remaining :|50 per cent. is to be painted white. Applied to a surface such as indicated at y, approximately 30 degrees; from horizontal, the needle points to the first (half) zone and the scale shows that such surface is to be painted black. And when applied to a surface such as z, the pointer -will indicate that the surface lies withinthe ninth zone and, as the scale shows, is to be painted with a mixture containing only 2 per cent. of black and hence 98 per cent. of white, or that 20 per cent. of its area is to be painted black and the remainder white.

Substantially all of the surfaces of a ship will be found to be within three or four of the different zones; and, in practice, it has proven convenient to have a foreman or the head painter go over the ship with thel scale, or after suliic1ent experience without needing to use a scale, and with chalk to outline the zones on its surfaces and to indicate in each the blend of colors to be used therein.

The terms black and white as herein used are to ybe understood as designating colors which are essentially dark and light, res ectively. r aving explained the principle of my inventlon and vdescribed and illustrated what l faces 1,aee,7fiev y L! I now consider to be the best means to be employed for carryingl the invention into practical operation, w at I claim as new, and desire to secure by Letters Patent, vis

1. The process of reducin the visibility of an object which consists in dividing the surfaces of the object into a plurality of zones and in giving to the surfaces within the different zones dil'erent color tones, the `single color tone of the surfaces within each zone being graduated from dark to light substan-l tially accordin to the a proximate average illuminating e ect of li Ilit thereon.

2. The process of iedgucing the visibility ofan object which consists 1n dividing the surfaces of the object into a plurality of zones and in painting the surfaces within the different zones with different blends of dark and light colors so as to give the surfaces within each zone a single color tone which is graduated from dark to light substantially accordin to the ap roximate average illuminatin'g e ect of lig t thereon.

8. he process of reducing the visibility of an ob'ect which consists in painting suraving ditl'erent angles of incidence different shades of color which are graduated from dark to light by xnixin together dark and light colors proportions the light color to the sine and the dark color tov the complement of the sineof the angle of incidence of the surface.-

4. The process of reducing the visibility of an object which consists in dividing the surfaces of the object into a plurality of zones representing substantially equal gradations of illumination based upon an approximate average zero angle of incidence and giving to t e surfaces Within the different zones different color effects graduated from dark to 1i ht substantially as the cosines of the ang es of incidence at the centers of illumination of the respective zones.

5. The process of reducing the visibility of an object which consists in paintin the different surfaces of the object di erent shades of color graduated from dark to light by mixing together lfor each different surface dark and light colors proportioned the dark to the light colors substantially as the complement of the sine of the determined averarg angle of incidence of that surface.

6. e process of reducing the visibility of an object which-consists in dividing the surfaces of the object into a plurality of zones representing according to an assumed average zero angle of incidence substantially faces within different zones given different color tones, the single color tone given to the surfaces within each zone being gi'adu` ated from dark to light substantial according to the a proximate average il umil hating effect of ight thereon.

8. s a new article of manufacture, an object the surfaces of which have been divided into a lurality of zones and the surfaces within t e different zones painted with different blends of dark and light colors so as to give the surfaces within each zone a sin le color tone which is graduated from dar to light substantially according to the ap roximate average illuminating eii'ect of lig t thereon.

9. As a new article of manufacture, an object the different surfaces of which .ire painted with different blends of color which are graduated from dark to light by mix-ing to ether dark and light colors proportioned su stantiall the light color to the sine and the dark co or to the complement of the sine of the angle of incidence of the surface.

10. As a new article of manufacture, an object the different surfaces of which are divided into a plurality of zones representing accordin to an approximate average zero angle of incidence substantially cqualgradations of illumination and the surfaces within -the different zones so treated as to present different color effects graduated from dark to light substantially as the cosines of the angles of` incidence at the centers of illumination of the respective zones.

l1. As a new article of manufacture, an object the surfaces of which are divided into a plurality of zones representing approximately equal gradations of illumination and the surfaces within the different zones are pa-inted with a blend of light and dai-k colors proportioned the .iight to the dark substantially as the sincs to the complements of the eines of the angles of incidence at the centers of illumination of the rcs ective zones. GEROlt BRUSH.

copies of this patent muy be obtained tor nire cento elch, by addressing the Commissioner of Patents,

. Wnhlngton, D. 0. 

